Automatic pilot



July 25, 1950 P. A. NOXON EIAL AUTOMATIC PILOT 5 Sheets-Sheet 1 Original Filed Dec. 31, 1945 M m Q IN E 355 ENTOR PaJJZA NOxOu/ BY ME.

@TORNEY.

July 25, 1950 P. A. NOXON ETAL 2,516,796

AUTOMATIC PILOT Original Filed Dec. 31, 1943 5 Sheets-Shae: 2

302 INVENTR5 3C6 PvuZ/fl mNoxdOll/ BY M Bil [Hunky A 7 TURNEY July 25, 1950 P. A. NOXON ETAL 2,516,796

AUTOMATIC PILOT Original Filed Dec. 31, 19.43 5 Sheets-Sheet 3 I N V EN TORS Poll], A .NOJCOIC/ BY M B Murphy A TTOENEY.

July 25, 1950 P. A. NOXON ET AL 2,516,796

AUTOMATIC PILO';

Original Fi led Dec. 31, 1945 5 Sheets-Sheet 4 V INVENTORS Paul AJVOXDIL BY MliMurpfiy TT'ORNEY.

July 25, 1950 P. A. NOXON ETAL 2,516,796

AUTOMATIC PILOT Original Filed Dec. 31, 1945 5 Sheets-Sheet 5 IN V EN TORS Pcujl Aivoxozz/ BY .B-

Patented July 25, 1950 AUTOMATIC PILOT Paul A. Noxon, Tenafly, and Norman B. Murphy, West Englewood, N. J assignors to Bendix Aviation Corporation, Tet'erboro, N. J a corporation of Delaware Original application December'tl, 1943, Serial No. 516,489. Divided and this application May 22, 1945, Serial No. 595,236

21 Claims. 1

This invention relates generally to automatic pilot or control systems for dirigible craft or the like having novel provision therefor for imparting an automatic turn to the craft in the manner more fully described and claimed in copending application Serial No. 516,489, filed December 31,

1943, and more particularly to a novel panel arrangement for initiating and controlling such turn, the present application constituting a division of the aforementioned copending application.

Where parent application Serial No. 516,489 deals with the system as a whole for maneuvering a dirigible craft into an automatic turn without calling upon the master instruments to initiate the turn thus leaving the latter free to respond to only those functions of normal course change, rate of course change and attitude change for which they were designed, the present application deals with the novel control panel for the system and the arrangement of instruments thereat for initiating and controlling a desired turn independently of the master instruments.

An object of the present invention, therefore, is to provide an automatic pilot system for dirigiole craft witha novel automatic turn mechanism.

Another object of the invention is to provide a novel automatic turn provision for an automatic pilot or steering system whereby correctly banked turns at any desired rate may be automatically obtained.

A further object is to provide a novel control panel for an aircraft automatic pilot which upon manual manipulation will maneuver the craft into an automatic turn at the correct banking angle "for a desired turn, an airspeed adjustment being provided on the panel to assure correct angles of bank for widely differing airspeeds.

Another object of the invention is to provide a compact and novel control panel for an automatic pilot embodying a novel automatic turn mechanism therein of the character described for controlling the direction and attitude of a craft, the panel being provided with pitch and bank trim knobs for readily trimming elevator and aileron surfaces as required during linear flight.

By manipulation of the pitch trim knob, for example, the craft may be made to climb or dive and and will continue to climb or dive at an angle corresponding to the setting of the pitch r trim knob until the latter is returned to a central position. Moreover, a single turn control knob is provided on the panel whereby the craft may be made to turn at any desired rate, the correct .angle of bank for that turn as well as the necessary amount of elevator trim for that turn-being 2 simultaneously introduced upon operation of the turn control knob.

The above and otherobjects and advantages of the present invention will appear more fully hereinafter from a consideration of the detailed description which follows, taken together with thcaccompanying drawing wherein one embodiment of the invention is illustrated. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only, and are not designed as a definition of the limits of the invention.

In the drawings, wherein like reference characters .refer to like parts throughout the several views:

Figure *1 is a diagrammatic illustration of an automatic control system for dirigible craft embodying the novel automatic turn control panel of the present invention;

Figure 2 is a front elevation view of the novel control panel of the present invention;

Figure 3 is a section view taken substantially along line 3-3 of Figure 2;

Figure 4 is a section view taken substantially along line 44 of Figure 2;

Figure 5 is a rear view with the cover removed of the control panel of Figure 2;

Figure 6 is a bottom view of the structure of Figure 5;

Figure 7 is a front elevation view of the structure of Figure 2 with the front panel removed;

Figure 8 is a section view taken substantially along line 8-8 of Figure 7;

Figure 9 is a section view taken substantially along line 9-9 of Figure '7; and

Figure 10 is a detail view of a portion of the structure of Figure 4.

Inasmuch as the novel control panel of the present invention constitutes an integral part of the automatic pilot system of copending application Serial No. 516,489, a general description of the latter system will be given as an aid to a better understanding of the various components of the novel control panel hereof and their individual and combined functions.

As diagrammatically shown in Figure 1 of the drawings the automatic pilot comprises a magnetic field pick-up device, generally designated with the reference character ID, in the form of a gyro-stabilized earth inductor compass, for generating an electrical signal during craft deviation from a prescribed course, proportional to the amount of deviation, for energizing a rudder system H to actuate a rudder 12; a rate of turn responsive gyro I3 adapted for generating an electrical signal proportional to the rateof 3 turn which is superimposed upon the directional signal to modify the energization of the rudder servo system H; and an artificial horizon gyro l4 having bank and pitch take-ofis I5 and [6 for generating signals inproportion to the bank and pitch of the craft for energizing aileron and elevator servomotor systems I! and IE to actuate delta connected coil 26, which may be termed as the secondary winding of the device. Coil 26 .is provided with three taps for connecting it by way of leads 2? with a three-phase wound stator 28 of an inductive coupling device 29 suitably mounted within a master indicator 30.

Coupling device 29 is provided with an angularly movable rotor winding 3| inductively associated with the stator windings 28 and carried able vacuum tube amplifier 33 by way of leads 34, the output of the amplifier feeding by way .of leads 35 to one phase winding 36 of a, two

phase induction motor 37, the second phase winding 38 ofwhich connects with the source of A. C. current through a suitable frequency doubler 39, the latter also being provided with a conventional phase shifting network to maintain the voltages within the two phase windings substantially 90 apart for proper operation.

Motor 31 has a rotor 46 carried by a shaft 4i provided at its outer end with a pinion 42 adapted .for driving through a speed reduction gear system 43, a gear 44 fastened to rotor shaft 32. A

gear 45, supported by the free end of shaft 32,

meshes with a gear 46 having connected thereto a hollow shaft 41 supporting by way of an arm 48 the shaft of a worm gear 49 which meshes with a worm 50 formed on or carried by a spindle shaft 5| which is received within hollow shaft :41. An annular compensator 52 having a series of adjusting screws 53 in engagement therewith is contacted by a follower 54 supported by an arm 55 fastened to the shaft of worm 49. In

.addition to any motion imparted by rotor shaft 32 to spindle shaft 5|, the latter is thereby also moved a small angular amount in one direction or another depending upon the contour of element 52 engaged by follower 54.

An indicating dial 56 is mounted on one end of spindle shaft 5| for cooperation with a fixed index 51 while the opposite end of the spindle is provided with a gear 58 for meshing with a gear 59 carried by a shaft 60 supporting a magnetic ,;rotor El thereon which is magnetically coupled with a stator winding 62 of an electromagnetic transmitter, the latter being adapted for connection to a similar device acting as a receiver :1ocated at a remote station to reproduce the indication of heading.

The free end of rotor shaft 32 carries through a resilient. supporting member 63 one-face 64 l of a magnetic clutch. A cooperating clutch face 65 is supported by a, suitably journalled shaft 66, Y 1 ibothclutch faces 64,, 6 5;being formedv of magby a shaft 32 for angular motion relative thereto. .Winding 3! is connected (to the input of a suit- 4 netic material. A coil 61 surrounds the clutch faces and has one end thereof grounded as at 68 and the other end thereof connected with a battery 69 by .way of a normally closed control switch at the novel control panel to be presently described, a lead 10, contacts H of a servo clutch switch 12 and contacts 13 of a power switch 14.

With the closing of switches 14 and 12, and the control switch at the panel, coil 61 is energized and clutch faces 64, 55 are brought into driving engagement whereby any motion of shaft 32 is transmitted to shaft 65 which also supports thereon a rotor winding 15 inductively associated with a three phase wound stator 16 of an inductive transmitting device ll.

Two lever arms 18 and 19 are provided within the master indicator which are pivoted on fixed pins and 8! and interconnected through a resilient member 82 anchored to both arms slightly below pivot pins 80 and SI. A bracket 83 is fastened to shaft 68 and is provided with a pin 84 positioned in between arms 18 and 19 so that upon clockwise rotation of shaft 66, for example, pin 84 will move arm 19 outwardly when a turning torque is exerted on shaft 66, spring 82 returning the arm and pin as well as shaft 66 to neutral when the torque is no longer applied, that is, when the clutch is disengaged, while upon a counterclockwise rotation of shaft 66, pin 84 urges arm 18 outwardly, the arm returning pin 84 and shaft 66 to neutral under the action of spring 82 when the turning torque is released. As a result of the foregoing provision the rotor winding 15 of transmitter 11 will always be urged to and maintained at an electrical zero prior to the engagement of the automatic steering system. This means that no matter how much the craft course has been changed, once it is placed on a desired course and the automatic pilot is engaged, rotor winding 15 will only have a signal generated therein of an amount proportional to the angle of deviation by the craft from the desired course.

Element 2| of the magnetic field pick-up device together with its primary and secondary windings is stabilized and maintained in a horizontal plane by means of a stabilizing gyroscope generally designated with the reference character 85, so that a compass is provided in which, for all practical purposes, turning and acceleration errors are eliminated.

Upon a craft departure from a prescribed course, the voltages induced within coil 26 of the pick-up device are varied to vary the voltages at coupling stator 28 whereby a signal is induced within rotor winding 3! proportional to the amount of craft departure from its course, which is amplified within amplifier 33 to energize phase Winding 36 of motor 31, the second phase being continuously energized from the source of alternating current. Rotor 40 of motor 3'! drives shaft 32 and rotor winding 3! to a null position. At the same time, assuming clutch faces 64, 65 to be in driving engagement,,rotor winding 15 of transmitter Tl is moved angularly relative to stator winding 18 and a signal is induced therein proportional to the amount of craft departure from its prescribed course. This signal is fed by suitable leads 86 to the input of a servo vacuum tube amplifier 81 and out therefrom by way of outlet leads 88 through a servo adapter 89 to energize one phase winding 90 of an induction motor 91, the second phase winding 92 of which is continuously energized from the, craftssource of ,-A. C'. current.

theoperation of the motor.

A driving connection between motor BI and rudder I2 is established by way of a servo clutch comprising a clutch face 93 mounted upon a shaft 94 carrying a'pinion 95 thereon for engagement with a speed reduction gear system 96 supported within a relatively stationary servo casing 91 for driving a rudder shaft 98 connected by means of cables 99 with rudder I2, and a second clutch face I fastened to a shaft IOI keyed to a gear 402 but adapted for longitudinal motion relative there-to, gear I02 connecting with a pinion I03 of motor 9i through an idler gear I04. The free end of shaft Hill has an enlarged portion defining an'abutmentfor one end of a spring member I05, the other end of which rests against gear I02.

The actuating means for axially moving shaft I'0I to the right to force clutch face I00 to drivably engage clutch face 93 comprises a solenoid coil I06 grounded at one end by way of a lead 161 and connected to one of contacts ll of servo clutch switch 12 by way of a lead I08. With switch 12 closed, a core I09 of the solenoid is urged to the right against the action of a spring 105 to axially move shaft lill therewith to provideengagement of the clutch faces so that motor =91 drives rudder H.

In driving gear I62, motor in also angularly displaces a rotor winding H6 of an inductive follow-back device having a three-phase wound stator I I I, the rotor being supported by a shaft H2 having a pinion H3 which is drivably connected to gear 5132 through a suitable speed reduction gear train H Displacement of rotor winding H0 relative to stator windings III generates an electrical follow-back signal which is fedby means of leads I It to amplifier 81 through servo adapter-80 to be impressed upon the direction signal within the amplifier to thereby modify The I follow-back signal opposes the direction signal and at such time that the follow-back signal is equal and op posite to the direction signal motor 9| becomes de-energized.

When the craft departs from its prescribed course it develops a certain amount of angular "velocity which is taken into account in the con- '-'trol of rudder I2 by the provision of the rate gyro I3 which comprises a rotor lit having normally horizontal spin axis supported by way of inner trunnions ill within a ginibal ring H8, the latter being mounted upon a rigid support by way of trunnions H9 and I for oscillation about a,

source of A. C.current.

The windings of stator L23 connect by way of leads I29 with a three-phase wound stator I30 of an inductive repeater or receiver device I3I likewis provided with a rotor winding I32 which is connected to adapter 89 by way of leads I33 to be superimposed upon the follow -back signal to further modify the operation or" motor 9| when the craft-departs from a predetermined course. Due to such departure, the induced voltages within stator I28 vary causing-a corresponding change in the voltages of stator windings I30 whereupoiia, signal proportional to the rateoi turn is generated within rotor winding I32 to be algebraically added to the direction and followback signals energizing phase winding 90 of motor 9|.

For aileron'and elevator control horizon gyroscope '14, which may be an artificial horizon, has a horizon bar rl351mounted for up and down movement relative to a mask I36 for designating craft .pitch, the mask, in turn, being adapted for angular movement relative to the bar for designating craft bank. The gyro per se may comprise an electrically drivenrotor I31'having norm-ally vertical spin axis mounted within a rotor bearing frame I38 provided with inner trunnions I39 mounting the rotor and frame within a gimbal ring I40 for oscillation about a first horizontal axis, the gimbal having an outer trunnion 'I4I' mounting it for oscillation about a second horizontal axis perpendicular to the first.

Bank take-ofi I 5 comprises an inductive transmitter device I42 having a rotor winding I43 carried by outer trunnion MI and energized by the crafts source of alternating current, rotor I43 being inductively associated with a three-phase wound stator I44 which connects by way of leads I45 with a three-phase wound stator I46 of an inductive repeater or receiver device I41 having a rotor winding I48 inductively coupled therewith so that any change of voltages caused within stator I44 due to angular movement of rotor winding I43 creates a like change in the voltages of stator I46 whereby a signal is induced within rotor winding I48 proportional to the amount of craft bank.

The signal induced within rotor winding I48 is fed into amplifier 81 'by way of leads I49 and fed out therefrom through servo adapter 89 by way of outlet leads I50 to one phase winding I5I of a two phase induction motor I52, the second phase winding I53 of which is continuously energized from the crafts source of A. C. current. Motor I52 constitutes a part of the aileron servo system I1 and a driving connection is established between it and ailerons I9 through a solenoid operated clutch which comprises two clutch faces I54 and I55, the latter being carried by a shaft I56 provided with a pinion I51 for driving aileron driving shaft I58 through a speed reduction gear system I59 supported within a relatively stationary casing I60, and clutch face I54 being carried by a shaft I6I which has a gear I62 keyed thereto but is adapted for axial movement relative thereto. Gear IE2 is driven by motor I52 through an idler I63 which meshes with a pinion I64 carried by a motor shaft I65.

Clutch faces I54 and I are normally held disengaged by virtue of a resilient spring I66 which abuts gear IE2 at one of its ends and an enlarged portion of shaft I6I at its other end to urge the latter shaft to the left. The actuating means for axially moving shaft IBI to the right to force clutch face I54 to drivably engage clutch face I55 comprises a solenoid coil I61 which is connected to conductor I01 at one end to ground and 'at its other end to contact H of switch 12, by way of a lead I08. With switch 12 in its on position, i. e., with contacts 1I engaged, coil I61 is energized to urge a core I68 to the right against the action of spring I66 whereupon shaft I6I is moved to the right to bring clutch faces I 54 and I55 into engagement whereby a driving connection is established between motor I52 and ailerons I9.

In driving gear I62, motor I52 also angularly asrcrzee displaces a rotor winding I of an inductive follow-back devicehaving a three-phase wound stator I1I, the rotor winding being inductively coupled with the stator and being carried by a shaft I12 having a pinion I13 thereon which drivably connects with gear I62 through a suitable speed reduction gear train I14. Displacement of the rotor winding relative to stator I1I during operation of motor I252 generates an electrical follow-back signal which is fed by way of leads I15 to amplifier 81 through-servo adapter 89 to be impressed upon bank signal within the amplifier to modify operation of motor I52. The follow-back signal opposes the bank signal and at such time as the follow-back signal becomes equal and opposite to the bank signal motor I52 becomes de-energized.

Pitch take-off I6 comprises an inductive transmitter device having stator windings I16 provided with three taps, the windings being energized from the crafts source of A. C. current by virtue of leads I11. A rotor I18 in the form of a magnetic vane is inductively associated with the stator and is secured to inner trunnion I39 for angular movement relative to the stator windings. The stator windings I16 connect by way of leads I19 with a three-phase wound stator I89 of an inductive repeater or receiver device having a rotor winding IBI inductively associated therewith so that any change in voltages caused within stator windings I16 due to angular movement of rotorv I18 creates a like change in the voltages of stator I 80 whereby a signal is induced within rotor I8I proportional to the amount of craft pitch.

The signal induced within rotor winding I8I is fed by conductors I82 to amplifier I81 and out therefrom through servo adapter I89 by way of outlet leads I83 to one phase winding I34 of a .two phase induction motor I85, the second phase Winding I86 of which is continuously energized from the crafts source of A. C. current.

Motor I85 constitutes a part of the elevator servo system I8 and a driving connection is established between it and elevator surfaces through a solenoid operated clutch which comprises two clutch faces I81 and I88, the latter being carried by a shaft I89 provided with a pinion I90 foroperating elevator driving shaft I9I through a speed reduction gear system I92 supported within a relatively stationary casing I93, and a clutch face I81 being carried by a shaft I94 which has a gear I95 keyed thereto but is adapted for axial movement relative thereto.

Gear I95 is driven by motor I85 through an idler I96 which meshes with a pinion I91 carried by a motor shaft I98.

Clutch faces I91 and I88 are. normally.disengaged by virtue of a resilient spring I99 which abuts gear I95 at one of its ends and an enlarged portion of shaft I94 at its other end to urge the latter shaft to the left. The enlarged end of shaft I94 is engaged bya core 209 of a solenoid whose coil 201 is grounded at one end by being tapped to lead I01 and at its otherend is connected by way of lead I08 to one of contacts H of switch 12. With the switch in its on position, 1. e., with contacts 1| engaged, coil 20I is energized to urge core 209 to the right whereupon shaft I94 is moved to the right to bring clutch face I81 into engagement with clutch face I88 whereby a driving connection is established between motor I85 and elevators '20.

In driving gear I95, motor I85 also=angularly displaces airotor winding 2050f. an inductive 8,; follow-backdevice having a three phase ,woujnd' stator 206, the rotor being inductively coupled with the stator and supported by a shaft 201 having a pinion 208 which is drivably connected togear I95 through a suitable speed reduction gear train 209. Displacement of rotor winding 205 during operation of motor I85 generates an electrical. follow-back signal which is fed byway of leads 2 I 0 to amplifier 81 through servo adapter 89 to beimpressed upon the pitch signal within the amplifier to thereby modify operation of motor I85. The follow-back signal opposes the pitch signal and at such time that the follow-back signal is equal and opposite to the pitch signal motor I85 becomes de-energized.

With servo clutch switch 12 in an open or off position, even though power switch 14 is closed, coil 61 of the magnetic clutch within master in-. dicator 30 is de-energized so that clutch face 66 is disengaged from clutch face 65 and simultaneously solenoid coils I 06, I61 and 29I of the rudder, aileron and elevator servo systems are de-energized whereby motors 9|, I52 and I 85 are disconnected from their respective control surfaces so that subsequent control of the rudder, aileron and elevator surfaces may be performed manually in the conventional manner.

Coming now to the novel control panel of the present invention and the arrangement thereat of the various components comprising the auto.- matic turn control mechanism of the parent application hereinabove referred to, the former is shown diagrammatically in Figure 1 as encased within a casing 2I5 which includes principally the inductive rate, bank and pitch repeater or receiver devices. As shown in this figure, stator I46 of the inductive bank receiver device is mounted for angular motion relative to its rotor I49 by means of a shaft 2I6 which connects through a suitable gear train 2I1 with a shaft 2 I 8 carrying a bank trim knob 2 I 9 thereon. Rotor winding I48 of this device is supported for angular motion relative to stator I96 by a shaft 220 which, at one of its ends, has secured thereto a bracket 22I provided with a pin 222 engaging a slot 223 of a lever 224 and at its other end carries a cam member 225 cooperating with a lever 226 together with a gear 221 which meshes with another gear 228 fastened to a shaft 229 carrying a turn knob 230 at the free end thereof. Also car'- ried by shaft 229 adjacent gear 228 is a wheel 23I provided with a notch in which normally rests an arm 232 carrying a contact 233 normally engaging a second contact 234, one of which is connected to coil 61 of the magnetic clutch of the master indicator and the other of which is con nected to lead 10 whereby coil 61 is in closed oir cuit with battery 69.

Stator I30 of the inductive rate receiver device, on the other hand, is stationary but its rotor I32 is mounted for angular movement relative to the stator by means of a shaft 235 which carries a bracket 236 supporting a pin 231 there-'- on which engages with a second slot 238 of lever 229. The lever itself is supported by a bracket 239 which is fastened to a toothed rack 240 meshing with a pinion 2 carried by a shaft 242 having an airspeed adjustment knob 243 at its free end.

The inductive pitch receiver device has its rotor I8I mounted for angular motion relative to stator I by means of a shaft 244 which is fastened to lever 226 whereby upon movement ,of cam 225 lever 226 is swung in a clockwise direction to .move shaft244 and rotor I8I. Stator I80; on the other hand is mounted for angular motion relative to rotor I8I by means of a shaft 245 which connects through a speed reduction gearing 248 with a pitch trim knob 24'! carried by a shaft 248.

For unequal loading conditions or for a condition wherein for some reason or another the condition of equilibrium between the inductive transmitting device I42 of the bank take-off and the inductive receiver device I4! has been destroyed, the bank trim knob 2I9 may be operated to angularly displace stator I46 in one direction or another relative to rotor I48 until the condition of balance has been re-established.

With the automatic pilot engaged, the craft may be forced into a climb by operating pitch trim knob 24! whereby stator I88 is displaced relative to its rotor I8! and it will be maintained in such climb until knob 24'! is returned to neutral. To bring the craft into a dive, knob 24? is operated in a reverse direction to reverse movement of stator I80 whereby the signal induced in rotor I8! is reversed to thereby reverse opera tion of the elevator servo system I8.

If, during the course of linear night with the automatic pilot engaged, it is desired to change course, the human pilot need merely displace knob 230 an angular amount proportional to the rate of turn desired. Operation of knob 230 turns wheel 23! so that arm 232 is forced outwardly from the notch of the wheel and contacts 233 and 234 become disengaged whereby the circult to coil 6'! of the magnetic clutch of the master indicator is open to de-energize coil 61 and inductive transmitting device TI is disconnected from the inductive coupling device 29 so that the direction signal no longer acts to energize motor SI of the rudder servo system. At the same time, gear 228 is turned with knob 230 and it, by virtue of being in mesh with gear 221, displaces rotor I48 relative to stator I46 thereby creating a condition of electrical unbalance between the stator and the rotor so that a bank signal is generated within rotor I48 even though at that moment the artificial horizon shows no bank and bank takeoff I is in a neutral position.

Motion of rotor I48 simultaneously causes angular movement of bracket 22I' and pin 222, the latter by virtue of its engagement with slot 223, pivots lever 224 about a pin carried by sup porting bracket 239. Movement of lever 224 also displaces pin 23''! which results in angular motion on the part of rotor I32 relative to its stator I30, such motion creating an electrical unbalance resulting in a rate signal being generated in rotor I32 notwithstanding the fact that at that moment the craft is in linear flight and rate gyro I3 as well as the rate'take-oif are in a neutral position.

As turn knob 238 displaces rotor I48 it also angul'arly displaces cam 225 which pivots lever 226* to angularly displace rotor I8! relative to itsv stator I8il. Thus, an electrical imbalance is created between the two resulting in the generation of a pitch signal within rotor IBI even though the craft at that moment is in a. level, attitude so that pitch take-off I5. is in a neutral position. Whether the desired turn be to the right or to the left of a given course, rotor I8I will be displaced in; one direction to provide a signal calling for up-elevator in either case to overcome the tendency of the craft to dive when the turn is initiated.

By operation of knob- 23!! the conditions for a desiredturn are automatically established without loading or calling'upon therate gyroor the 10 artificial horizon to control the turn. The signals set in by the turn knob are fed into their respective networks to control related surfaces to swing the craft into a desired turn at the correct angle of bank for that turn together with the necessary lip-elevator.

The automatic turn is accomplished and maintained as long as desired by reason of the fact that the rate signal generated within rotor I32 is fed by leads I33 and adapter 89 to the rudder servo network of amplifier 87 and out therefrom by way of leads 88 to energize phase winding 90 of motor 9I. Rudder I2 is actuated by motor 9| and, at the same time, rotor I I0 of inductive rudder follow-back device is displaced angularly relative to stator III whereby a follow-back signal is generated and fed by leads I I5 to the rudder network of the amplifier. The rudder is deflected until the follow-back signal is equal and opposite to the rate signal at which time motor 9 I becomes deenergized.

At the same time, the bank signal generated within rotor I48 is fed by leads I49 to the aileron network of amplifier 81 and through adapter 89 and leads I 49 to phase winding I5I of motor I52. Ailerons [9 are actuated by motor I52 and at the same time rotor I10 of the inductive aileron follow-back device is displaced angularly relative to its stator I II whereby a follow-back signal is generated and fed by leads I15 to be superimposed upon the bank signal and the aileron network of the amplifier. The ailerons are actuated outwardly until the follow-back signal is equal and opposite to the bank signal at which time motor I 52 becomes de-energized.

This same operation takes place as a result of the pitch signal generated within rotor IBI. The signal so generated is fed into the elevator network of the amplifier by leads I82 and out therefrom by Way of leads I83 to energize phase winding I84 of motor I85. Elevators 2B are actuated by motor I85 and, at the same time, rotor 205 of the inductive elevator follow-back device is displaced relative to stator 285 whereby a followback signal is generated and fed by leads 2 II] to be superimposed upon the pitch signal in the elevator network of the amplifier. The elevators are actuated outwardly until the follow-back signal is equal and opposite to the pitch signal at which time motor I85 becomes de-energized.

With the operation thus far described, craft will be swung into the desired turn with rudder, ailerons and elevators displaced as described. The direction, rate of change of course and the banked attitude of the craft all are registered by dial 56 of the master indicator, pointer I25 of gyro I3, and the mask and bar arrangement of horizon I4. The ensuing displacements of rotor I2'I' relative to stator I28 of the rate take-off and rotor I43 relative to stator I44 of the bank takeofi, re-establish the position of electrical equilibrium with the rate and bank inductive devices at the control panel so that the rate signal within rotor I32 disappears and the bank signal of rotor I48 likewise disappears. Because both rotors I I II and H0 of the inductive follow-back devices of the rudder and aileron servo systems are at that moment displaced from their nulls and signals are effective through the rudder and aileron networks of amplifier 87 to reverse operation of motors BI and I52 to bring the rudder and the ailerons to their neutral positions. Thus, after the craft assumes the proper turn at the correct angle of bank, the rudder and aileron surfaces will be back in their neutral positions. Should the craft turn at a slower or faster rate than that selected, rate gyro 13 will dominate to apply right or left rudder as the case may be to regulate the rate of turn to be maintained at the pre-selected value.

on approaching the new course, the turn may be terminated by operating knob 230 back to its neutral position. Such knob operation creates signals within rotors 132, 148 and 181 of the inductive receivers at the control panel, in a direction opposite to the direction of the signals generated when the original turn was initiated, which control the rudder, aileron and elevator surfaces in a direction to establish level attitude ofthe craft. As soon as the level attitude is attained, the condition of electrical equilibrium established between the rate, bank and pitch takeoffs and their related inductive receiver devices at the control panel so that the rate, bank and 'pitch signals within the rotors of the latter devices, set in with the return of knob 230 to neutral, disappear and the follow-back signals of the rudder, aileron and elevator inductive follow-back devices return the related control surfaces to their neutral positions.

"ting so made. Should, however, the speed of the craft be changed substantially, the proportional constant between the angle of bank and the rate of turn must be changed. This is accomplished by turning knob 243 which results in motion of rack 240 whereby the pivot point of lever 224 is moved relative to pins 222 and 231 of the bank and rate inductive receiver devices thereby changing the lever length of each of the devices.

Referring now to Figures 2 to 10, inclusive, of

the drawings, there is shown one practical embodiment of the novel control panel of the present invention for actuating the automatic turn mechanism shown diagrammatically in Figure 1 and described more fully in the above referred to copending parent application. As shown in Figures 2 and 3, control panel 300 is suitably fastened by means such as screws 301 to a supporting casing 332 having a housing 303 therefor. The

exterior of the panel is provided with a bank trim knob 304, a pitch control knob 305 together with an automatic turn control knob 306 superimposed thereover, as well as a Vernier pitch trim knob 301. Also contained on the panel are power switch 308, servo clutch switch 309, a pitch trim indicator 310 and an airspeed adjustment knob 311 having a locking member 3110, therefor.

Bank trim knob 3114 is fastened to a shaft 312 (Figure 3), suitably journalled within casing 302, provided with a pinion 313 meshing with a gear sector 314 secured to the casing of an inductive repeater or receiver device 315 which is rotatably supported within a part of casing 3132 and having arranged therein a three phase wound stator I (similar to stator 146 of Figure 1). Actuation of fknob 304 angularly displaces the casing of device 3| 5 and its stator relative to the rotor (similar to the rotor 148 of Figure 1), so that an electrical unbalance i created between the two thereby generating an electrical signal within the rotor of device 315 independently of the bank take-off means arranged at the artificial horizon to which the device 315 is connected. Thus, the proper amount of aileron displacement is derived as heretofore explained in connection with Figure 1.

Pitch control knob 305 is fastened to a hollow sleeve 316, as better shown in Figure 3, which has secured thereto a pinion 311 for meshingwith a large gear 318, shown in dotted lines in Figure '7, the latter, in turn, meshing with a pinion 319 (Figure 4) carried by a sleeve 320 clamped to a hollow shaft 321 which at its free end supports a pinion 322. The pinion drives a gear 323 carried by a second shaft 324 which also supports thereon a pinion 325 meshing with a second gear 323 pinned to a shaft 321 which is arranged within hollow shaft 321. This gear reduction drive is more clearly shown in Figure 10.

One end of inner shaft 32'! carries pitch trim indicator 310 exterior of the panel and the other end of the shaft has a gear 328 fastened thereto for driving a gear sector 329 secured to the cas ing of an inductive repeater or receiver device 330 which is rotatably supported within a part of casing 302 and having arranged therein a three phase wound stator (similar to stator of Figure 1). Actuation of pitch control knob 3135 angularly displaces the casing of device 331) and its stator relative to the rotor (similar to rotor winding 181 of Figure 1) so that an electrical unbalance is created between the two thereby generating an electrical signal within the rotorof device 330 independently of the pitch take-off arranged at the artificial horizon to which device 330 is connected.

Thus, the proper amount of elevator displacement is derived to cause the craft to climb or dive as heretofore explained in connection with Figure 1. For fine adjustments desired during unbalanced loading conditions, pitch trim knob 301 is provided which may engage pitch control knob 305 through a suitable reduction gear (not shown). Trim indicator 310 indicates to the human pilot whether or not the elevators are in a neutral position.

By operating a single knob, i. e., turn knob 305, the craft may be swung into an automatic turn and maintained in such attitude until the knob is returned to its neutral position. As shown in Figure 3, knob 303 i fastened to a shaft 331 which passes through hollow sleeve 316 and carries near its free end a gear 332 which drives a gear 333 through a pinion 334, better shown in Figure 5. Gear 333 is sleeved 'or clamped to a shaft 335 of the rotor of inductive device 315 whereby motion of knob 306 causes angular displacement of the rotor relative to its stator so that a bank signal is generated in the rotor even though the bank take-off at the artificial horizon is in a neutral position. Displacement of the rotor of device 315 simultaneously causes :an angular displacement of the rotor of an inductive rate repeater or receiver device 3 36 (Figure 7) whose casing supporting the stator portion is also mounted Within a portion of casing 302 and also causes a displacement of the rotor of device 330.

This is accomplished by reason of a bracket 33! carried at the opposite end of rotor shaft 335, the bracket supporting the pin 338 (Figure 8) which cooperates with a slot 339 of the lever 340 pivoted on a pin 341 supported by a bracket 342 which is carried by a carriage 343. Lever 340 is provided with a second slot 344 with which cooperates a apropos;

pin 345 carried by a bracket 346 fastened to a shaft 34! of the rotor of device 336. A spring 343 anchored atone end to a portion of casing 302 connects at its other end to lever 340 to absorb any backlash in the system. Thus, motion on the part of rotor shaft 335 results in angular motion of rotor shaft 34! whereby a rate signal is generated' in the rotor of device 336 even though at that moment no signal is being called for by the rate gyro take-off.

' As more clearly shown in Figure 5, the end of shaft 335 supporting gears -3!4 and 333 thereon also supports two spaced cam members 349 and 350 which may be adjusted either outwardly or inwardly with respect to each other by virtue of screws 35! (see Figure 8). In engagement with the cams is a lever 352 and has a spring 354 anchored thereto at 353, the opposite end thereof being anchored to casing 302. The opposite end of'lever 352 is provided with a bracket 3 55 which is fastened to a shaft 355 of the rotor of device 33!! whereby motion of lever 352 angularly displaces the rotor relative to its stator so that an electrical signal is generated in the rotor of device 3'30even thoughat that moment no signal is being called for by the pitch take-off at the artificial horizon.

The extreme end of turn knob shaft 33! is provided with a wheel 360, Figure 7, having a single notch at its outer periphery in which normally rests a finger 36!, pivoted at 362, and carr ing a trip member 363 which abuts one of two contacts (similar to contact 233 of Figure 1) mounted within a suitable switch box 364. Thus, immediately upon actuation of turn knob 305, the contacts (not shown) within switch box 364 are opened (see Figure l) to de-energize coil 6'! of the magnetic'clutoh whereby the controlling connection between the magnetic field pick-up device and the motor 9! of the rudder servo system is opened, so that induction motor 9! is under the sole control of the rate signal as heretofore explained.

Power switch 308 of the panel operates contacts (not shown) arranged within a switch box 365 ,(Figure 6). This switch is similar to switch 14 of Figure 1 and its operation will .be understood from the description given relating to Figure 1. Throwing switch 308 from its off position to its on position closes contact 13 of Figure 1 and places one of the contacts l'! of the servo clutch switch .12, across battery 69.

Switch 39.9 arranged on panel 300. of Figure 2 likewise operates a pair of contacts arranged within a suitable switch box 305a mounted to'the rear of the panel, the contacts being designated at l! in Figure 1, With the throwing of clutch switch 309 from its.out to its in position, contacts I! of Figure I are closed so that servo solenoid coils H36, H38 and are energized to connect the induction motors to their respective control surfaces and at the same time coil 6! of the magnetic clutch is energized to establish a driving connection between the inductive coupling device 29 of the master indicator and the inductive transmitting device 11, assuming turn knob 30E1of the panel to be in its neutral position. Operation of switch 300 to its out position tie-energizes the solenoids as well as coil 61.

With switch 309 in its "in position and power switch 308v in its on position, actuation of turn knob 300 causes de-energization of coil 8'! and opens the driving connection between the rudder motort i and the magnetic field pickup device 14 butthe solenoids of the rudder, aileron and elevator servo systems remain energized.

Airspeed adjustment knob 3!! is fastened to a shaft 380, the latter being provided with a pinion 38! (Figure '7) for meshing with a toothed rack 382 fastened to carriage 343. Actuation of knob 3!! in one direction or another moves carriage 343i together with bracket 342 in one direction or another to thereby move lever 340 in one directionor another relative to pins 338 and 345. Such relative motion varies the lever length of lever 34!] so that in one position a given angular movement of the rotor of the device 3l5 will produce a given angular movement of the rotor of device 336 while in another position for the same angular movement of the rotor of device 3!5, a different movement will be imparted to the rotor of device 335 so that a varied signal is generated in the latter rotor to increase or decrease the value of the rate signal set in to compensate for widely varying airspeeds.

If desired, a pilots disconnect switch 400 may also be provided, which may be located on the pilots wheel so that if it is desired to de-energize the servo clutches, the pilot need merely depress a button iii! which connects a coil 402 to ground thereby energizing the coil whereupon a core 403 is urged outwardly to open servo clutch switch 12. As soon as switch 12 is opened, coil 402 is deenergized but does not close switch 12, the latter requiring a direct operation of the switch,

The novel automatic turn control panel above described is of such a character that extreme flexibility of control is provided by the automatic pilot which makes it possible to execute maneuvers by turning appropriate controls thereat. For example, sharply banked turns may be made by actuation of the turn control knob, the craft immediately returning to straight flight when the knob is returned to its central position. Steep climbs or dives may be made by operating the pitch trim knob. Moreover, a combination of turn and climbs or turns and dives may also be executed or the craft quickly thrown from a correctly banked turn in one direction to a correctly banked turn in an opposite direction.

Although but a single embodiment of this invention has been illustrated and described in detail, it is to be expressly understood that the invention is not limited thereto. Various changes may also be made in the design and arrangement of" the parts without departing from the spirit and scope of the invention, as the same will now be understood by those skilled in the art. For a definition of the limits of the present invention, reference will be had primarily to the appended claims.

We claim:

1. In an automatic pilot for aircraft, a control panel for said pilot, means comprising rate, bank and pitch signal repeater devices arranged at one side of said panel and connected to remotely located rate, bank and pitch master instruments, 2. control knob arranged at an opposite side of said panel for actuating said repeater devices independently of said master instruments, and means operatively connecting said knob to said repeater devices.

2. In an automatic pilot for aircraft, a control panel for said pilot, means comprising rate, bank and pitch signal repeater devices arranged at one side of said panel and connected to remotely located rate, bank and pitch master instruments, a pitch control knob at an opposite side of said panel for actuating said pitch repeater device independently of its related master instrument, a turn control knob on said panel coaxial with said pitch control knob for actuating said rate, bank and pitch repeater devices independently of their related master instruments, and means operatively connecting said turn knob to said repeater devices.

'3.- In an automatic pilot for aircraft, a control panel for said pilot, means comprising rate, bank and pitch signal repeater devices arranged at one side of said panel and connected to remotely located rate, bank and pitch master instruments, a pitch control knob at an opposite side of said panel for actuating said pitch repeater device independently of its related master instrument, an indicator at said opposite side of said panel for indicating the operation of said pitch repeater device, a turn control knob on said panel coaxial with and superimposed over said pitch control knob for actuating said rate, bank and pitch repeater devices independently of said master instruments, and means operatively connecting said turn knob to said repeater devices.

' 4. 'In an automatic pilot for aircraft, a control panel for said pilot, electrical rate of turn signal developing means, electrical attitude change signal developing means, both of said last-named signal developing means being mounted on one side of said panel and connected to remotely located rate of turn and attitude responsive master instruments, a turn control knob on an opposite'side of said panel for simultaneously actuating said rate of turn signal developing means and said attitude change signal developing means independently of said master instruments, and means operatively connecting said turn kndb to said rate of turn and said attitude change signal developing means.

5. In an automatic pilot for aircraft, a control panel for said pilot, means mounted on one side of said panel and normally having a signal generated therein proportional to the rate of turn by said craft from a prescribed direction, means mounted on said one side of said panel and having signals normally generated therein proportional to the bank and pitch of said craft when said craft departs from a prescribed attitude, a turn control knob on an opposite side of said panel for actuating both of said last-named means to generate desired signals therein differing from and independently of the signals normally generated therein due to craft maneuvers preceding actuation of said knob, and means operatively connecting said knob to said rate of turn, bank and pitch signal generating means.

6. In an automatic pilot for aircraft, a control panel for said pilot, means mounted on one side of said panel and normally having a signal gen- 'erated therein proportional to the rate of turn of said craft from a prescribed direction, means mounted on said one side of said panel and normally having signals generated therein proportional to the bank and pitch of said craft when said craft departs from a prescribed attitude, bank and pitch trim knobs on an opposite side of said panel for actuating said second-named means, a turn control knob on said opposite side of said panel for simultaneously actuating said first and said second-named means, and means operatively connecting said turn knob to said first and said second-named means.

7. In an automatic pilot for aircraft, a control panel for said pilot comprising a casing, means mounted within said casing having a signal normally. generated therein in proportion to the rate 16 of turn of said'craft when said craft departs from a prescribed course, other means mounted within said casing having signals normally generated therein in response to the pitch and bank of said craft due to its departure from a predetermined attitude, a mechanical linkage for'interconnecting said first-named means with said last-named means, a control knob exterior of said casing for operating said linkage to actuate both of said means for setting up rate, bank and pitch signals therein even though said craft is on said prescribed'course and in said predetermined attitude at the moment said knob is op erated, and an airspeed adjustment knob exterior of said casing connected to said linkage for variably setting the latter to compensate'for varying airspeeds.

8. In an automatic pilot for aircraft, a control panelfor said pilot comprising a casing, a rate signal repeater device mounted within said casing and having an angularly movable rotor therefor, a bank signal repeater device mounted within said casing and having a relatively angularly movable stator and an angularly movable rotor inductively associated therewith, a pitch signal repeater device mounted within said casing and having a relatively angularly movable stator and an angularly movable rotor inductively associated therewith, control knobs exterior of said casing for angularly displacing said bank and pitch stators, a turn control knob exterior of said casing for angularly displacing said rate, bank and'pitch rotors, and means operatively connecting said turn knob to said rate, bank and pitch rotors.

9. A control panel for an automatic pilot for aircraft, comprising a casing, a rotatable inductive rate signal device within said casing, a retatable inductive bank-signal device within said casing, a rotatable inductive pitch signal device within said casing, a turn control knob exterior of said casing for simultaneously actuating said devices, and means operatively connecting said knob to said rate, bank and pitch signal devices.

10. A control panel-for an automatic pilot for aircraft, comprising a casing, inductive rate, bank and pitch signal devices mounted within said casing, a bank control knob exterior of said casing for, actuating said inductive bank device, a pitch control knob exterior of said casing for actuating said inductive pitch device, a turn control knob exterior of said casing for simultaneously actuating all of said devices, and means operatively connecting said turn knob to all of said devices.

11. A control panel for an automatic pilot for aircraft, comprising a casing, inductive rate, bank and pitch signal devices mounted within said casing, bank and pitch control knobs exterior of said casing for actuating said inductive bank and pitch devices respectively, a Vernier adiustment for said pitch knob exterior of said casing, a turn control knob exterior of said casing for simultaneously actuating all of said devices, and means operatively connecting said turn kno to all of said devices.

12. A control panel for an automatic pilot for aircraft, comprising a casing, inductive rate, bank and pitch signal devices mounted within said casing, bank and pitch control knobs exterior of said casing for actuating said inductive bank and pitch devices respectively, a turn control knob exterior of said casing coaxial with'and superimposed over said pitch control knob for simultaneously actuating all of said devices, and

means operatively connecting said turn knob to all of said devices.

13. A control panel for an automatic pilot for aircraft, comprising a casing, inductive rate, bank and pitch signal devices Within said casing, a link connecting said bank device to said rate device, means connecting said bank device to said pitch device, and means comprising a turn control knob exterior of said casing connected to said bank device for actuating the latter whereby said link is operated to actuate said rate device and said connecting means are operated to actuate said pitch device.

14. A control panel for an automatic pilot for aircraft, comprising a casing, inductive rate, bank and pitch signal devices mounted within said casing, a movabl mounted link connecting said bank device to said rate device for actuation of the latter during operation of th former, means connecting said bank device to said pitch device, means comprising a turn control knob exterior of said casing connected to said bank device for actuating the latter whereby said link is operated to actuate asid rate device and said connecting means are operated to actuate said pitch device, and means comprising an airspeed adjustment knob exterior of said casing connected to said link for moving the latter to compensate for variations in airspeed.

15. A control panel for an automatic pilot for aircraft, comprising a casing, inductive rate, bank and pitch signal devices mounted Within said casing, means comprising a link connecting said bank device to said rate device, a movable carriage for supporting said link, means connecting said bank device to said pitch device, means comprising a turn control knob exterior of said casing connected to said bank device for actuating the latter whereby said link is operated to actuate said rate device and said connecting means are operated to actuate said pitch device, and means comprising an airspeed adjustment knob exterior of said casing connected to said carriage for moving the latter to compensate for variations in airspeed.

16. In combination with a casing having an open end, a control panel for closing the open end of said casing, means comprising rate, bank and pitch signal devices mounted within said casing, a pitch control knob mounted on said panel and connected to said pitch signal device for actuation thereof, a turn control knob mounted on said panel coaxial with said pitch control knob for simultaneously actuating said rate, bank and pitch signal devices, and means operatively connecting said turn knob to said rate, bank or pitch signal devices.

17. A control panel for an automatic pilot for mobile craft provided with a rudder and having course deviation responsive means together with rate of course deviation responsive means connected to said rudder for the control thereof, a rate of turn signal device on one side of said panel and connected to said rate of course deviation responsive means and to said rudder for rep eating the signal developed by said rate of course deviation responsive means during a craft deviation from a prescribed course, and means comprising a turn knob on the opposite side of 18 said panel connected to said rate of turn device for actuating the latter to develop a rudder control signal independently of the course deviation responsive means and the rate of course deviation responsive means.

18. A control panel for an automatic pilot for mobile craft provided with aileron and elevator surfaces thereon and bank and pitch signal master instruments for controlling said surfaces, bank and pitch signal repeaters on one side of said panel connected to said bank and pitch master instruments and to said aileron and elevator surfaces respectively for repeating the signals of said master instruments, and means on the opposite side of said panel and connected to said bank and pitch signal repeaters for actuating the latter selectively or in unison for developing signals therein independently of said master instruments.

19. In an automatic pilot for aircraft, a control panel for said pilot, means comprising turn, bank and pitch signal developing devices arranged at one side of the panel and connected to remotely located turn, bank and pitch responsive master instruments, a movable control element arranged at an opposite side of the panel for actuating said signal developing devices independently of the master instruments, and means operatively connecting said control element to said signal developing means.

20. A control panel for an automatic pilot for aircraft, comprising a casing, a rotatable induc-- tive turn signal developing device within said casing, a rotatable inductive bank signal developing device within said casing, a rotatable inductive pitch signal developing device within said casing, a movable turn control knob exterior of said casing for simultaneously actuating said de vices, and means operatively connecting said knob to said turn, bank and pitch signal developing devices.

21. A control panel for an automatic pilot for aircraft, comprising a casing, a turn signal developing device having a movable part mounted within said casing, a bank signal developing device having a movable part mounted within said casing, a pitch signal developing device having a movable part mounted within said casing, a movable turn control element exterior of said casing for simultaneously actuating said devices, and means operatively connecting said element to said turn, bank and pitch signal developing devices.

PAUL A. NOXON. NORMAN B. MURPHY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,801,948 Boykow Apr. 21, 1931 2,144,616 Carlson Jan. 24, 1939 2,203,671 Carlson June 11, 1940 2,270,875 Hanson et a1. Jan. 27, 1942 2,325,108 Carlson July 27, 1943 2,380,425 Frische et al July 31, 1945 2,415,430 Frische et a1 Feb. 11, 1947 

